Improved lithium storage performance of block-like Sn/SnO2 powders wrapped in the hydrogel-derived carbon layer as composite anode materials

Novel nitrogen–doped carbon (NC) coating encapsulating block-like Sn/SnO 2 (Sn/SnO 2 @NC) composite powders are successfully synthesized via hydrothermal, sol–gel, and subsequent heat treatment processes, which are characterized by XRD, SEM, thermogravimetric, Raman, and XPS. The results indicate that the Sn/SnO 2 @NC-2 composite powders are uniformly distributed in the NC matrix in the presence of 7.000 g of acrylamide. Moreover, the Sn/SnO 2 @NC-2 composite powders deliver high initial discharge specific capacity of 1132 mAh g −1 and decent capacity of 471.4 mAh g −1 after 100 cycles at 100 mA g −1 when the composite powders are evaluated as anode materials for lithium-ion batteries. The improved electrochemical performance of Sn/SnO 2 @NC-2 is mainly ascribed to the NC coating that can relieve the volume expansion and provide multiple charge transfer channels for electrons to consolidate the structural stability and promote the electronic conductivity of the Sn/SnO 2 anode materials, respectively. Therefore, the Sn/SnO 2 @NC-2 composite powders can be a promising and attractive anode material for lithium-ion batteries.